The entire disclosure of co-pending U.S. patent application Ser. No. 10/739,213 is incorporated herein by reference in its entirety.
Page annotation of documents including books, magazines, journals, textbooks, photo albums, maps, periodicals, or the like, is a common technique performed by readers and viewers of these documents. Page annotation is highly desirable to the readers and the viewers because it provides the readers and the viewers with the ability to mark the documents with text notes, handwritten notes, bookmarks, highlights and/or the like, to, e.g., facilitate later review of the same material by the annotater or another reader.
Although many of these documents have been traditionally presented in paper format, electronic formats of these documents have become widely available due to numerous developments in the computer related fields, e.g., the Internet. With the increasing growth of electronic documents, the readers and the viewers still find page annotation highly desirable. Therefore, some annotation tools for two-dimensional electronic documents have been provided.
For example, Schilit, Price, and Golovchinsky describe a research prototype called XLibris® used to display two-dimensional electronic document pages and support free-form annotations, which runs on a tablet computer and accepts pen input. By using the pen, the user can scribble notes, draw figures, and highlight text. The user also has the option of changing the color of the pen and/or selecting between a wide pen and a narrow pen.
PCT Publication WO 0,142,980 describes an annotation tool for annotating two-dimensional electronic documents. PCT Publication WO 0,142,980 describes that “the annotations are stored separately from the viewed document pages but are correlated with the pages such that when a previously annotated page is revisited, annotations related to that page are retrieved and displayed on top of the page as an ‘ink’ layer.” By using the stylus, the user can highlight certain parts of the two-dimensional document in translucent colors or mark opaque annotations on the page, in a way very similar to XLibris. To display the annotations, the “pixel blending function blends pixels from a document page with corresponding pixels from an annotation or ‘ink’ layer mapped to that document page, and generates a blended pixel image that is displayed as an annotated document page.”
PCT Publication No. WO 0,201,339 also describes an annotation tool for annotating two-dimensional electronic documents, and describes a technique which “analyzes the ink for each annotated pixel and renders the color and brightness of each pixel based on the original pixel color and the added annotation color so as to appear as physical ink would typically appear if similarly applied to physical paper.”